When you turn on a clothes dryer, you are setting the controls that operate the motor. The motor turns on a blower and rotates the drum. The blower pushes air through the exhaust duct. One or more thermostats linked to a timer control the heating element. As the clothes tumble, hot, dry air enters the drum, circulates through the clothes, and exits through the lint trap and out the exhaust duct.
As always, any time you are working with electricity, make sure the power is off or the appliance is unplugged.
Tools & Materials:
- Towel
- Screwdriver
- Putty knife
- Volt-ohmmeter
- Continuity tester
- Adjustable wrench
- Needle-nose pliers
- Wire cutters
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TROUBLESHOOTING GUIDE
Problem --- Probable causes ---- Solutions
--------------
Problem
Dryer doesn't run
--
Dryer runs but doesn't heat
--
Dryer runs but doesn't dry clothes
--
Drum doesn't rotate
---------
Probable causes
No power to dryer
Door opened or door switch faulty
Timer or timer motor faulty
Dryer motor faulty
--
Temperature selector switch faulty
Timer faulty
Thermostat faulty
--
Blocked lint trap or exhaust duct
Heating element faulty
Thermostats faulty
Heater element faulty
--
Broken belt
Broken tension spring
Dryer motor faulty
--
Solutions
Make sure dryer is plugged in. Check circuit breakers.
Close door.
Check door switch.
Test timer and timer motor.
Test motor; replace if necessary.
--
Check temperature selector switch.
Check timer and timer motor.
Check thermostat.
Check heating element.
--
Clean lint from trap and duct.
Check thermostats.
Check heating element.
--
Replace belt.
Replace spring.
Check and replace motor if necessary.
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Step 3-1.
Removing the control panel. Unplug the dryer and remove the two screws at the front lower corners of the control panel. Remove any screws on the top or sides of the control panel. Place an old towel on the top of the dryer for protection.
Step 3-2. Gaining access to the controls. Disconnect the control panel from
the top of the dryer and place it face down on the towel. Remove the screws
holding the rear panel in place. You now have access to the timer, temperature
selector switch, and start switch.
--- Step 3-3. Testing the timer.
Label the wires going to the timer, draw a wiring diagram, then disconnect the wires. Set the volt-ohmmeter to the R xl scale and turn the timer knob to the first setting. Touch one probe to each terminal on the timer. The needle should indicate continuity (move to 0) between at least one pair of terminals. Turn the control knob to the next setting and repeat the test. You should get continuity between one pair of terminals at each setting except OFF. When the timer is off, no pair of terminals should show continuity. If the timer fails the test, replace it. To replace the timer, remove the control knob from the front of the panel. Disconnect the old timer from the back of the panel. Install the new timer and reconnect the wires according to your wiring diagram.
----
Step 3-4. Testing the timer motor.
Disconnect the two wires going to the timer motor terminals. Set the volt-ohmmeter to the R x 1K scale. Touch a probe to each of the two motor terminals. The needle should move to approximately 2500 ohms. If the needle fails to move, replace the motor. Remove the two screws holding the motor in place, install the new motor, and reconnect the wires. For some models, you might have to replace the entire timer.
---- Step 3-5. Testing the temperature selector switch.
Label the wires and draw a wiring diagram showing where the wires connect to the switch. Disconnect the wires from the switch terminals. Set the temperature control to the heat setting you want to test. Set the volt-ohmmeter to the R x 1 scale. Touch one probe to one terminal and the other probe to the other terminal that corresponds with the temperature selected. (If you have a dial selector, refer to the manufacturer's wiring diagram in the control panel.) The meter should move to 0, indicating continuity. Repeat this test for each temperature setting on the selector switch. If no continuity exists at any temperature setting, replace the selector switch. Disconnect the old switch from the control panel. Install the new switch and reconnect the wires.
----- Step 3-6. Checking the start switch.
Label the wires and disconnect them from the switch's terminals. Set the volt-ohmmeter to the R x1 scale. If the switch has two terminals, touch a probe to each terminal. The needle should not move. Now press the start button and repeat the test. The needle now should move to 0. If the switch has three terminals, touch a probe to the terminal marked NC and the other probe to the terminal marked CO. The meter should swing to 0. Now press the start button. The needle should swing in the other direction, indicating no continuity. If your results are different, install a new switch.
--- Step 3-7. Gaining access to the door switch. Unplug the dryer. If your
dryer has a top-mounted lint screen, remove the screen and the screws at the
edge of the screen slot. Wrap a few turns of masking tape around the blade
of a putty knife. Insert the blade under the top panel a couple of inches from
each corner and push in on the hidden clips to release the top panel.
Step 3-8. Finding the door switch for another type of dryer. If your dryer does not have a top-mounted lint screen, open the door and remove the four screws under the front edge of the panel. Raise the panel and gently rest it on the hinges in the back.
----
Step 3-9. Testing the door switch.
The switch should be mounted near the upper corner of the door opening. Disconnect the two wires from the switch terminals. Using a continuity tester or a volt-ohmmeter I set to the R x 1 scale, touch a probe to each terminal of the switch. With the door open, the needle should not move, indicating no continuity. With the door closed, or the switch plunger pressed in, the needle should move to 0. Operate the switch manually several times to ensure that it is not sticking. If the switch does not work freely or it fails to check for continuity, install a new one.
Step
3-10. Testing the thermostats. Depending on the type of dryer, the thermostats
might be located on the blower housing and the heater box, on the heater housing,
or under the lint screen. Unplug the dryer and disconnect the exhaust duct.
Move the dryer out from the wall to gain access to the rear panel. Use a small
socket wrench or screwdriver to remove the rear panel. Locate the thermostats.
You might find three or four-test them all the same way. You should see two
wires going to each thermostat. Select a thermostat to test and disconnect
one of the wires from its terminal.
Set the volt-ohmmeter to the R x 1 scale, or use a continuity tester. Touch one probe to each terminal of the thermostat. If you are using a volt-ohmmeter, the needle should move to 0, indicating continuity. If you are using a continuity tester, the bulb should light. If any thermostat fails the test, remove it and install a new one.
------
Step 3-11. Testing the heating element.
With the dryer unplugged and rear panel removed, locate the heater box and the wires going to the heater terminals. If you don't see a heater box, the dryer has heating coils located in a heater housing behind the drum. If the dryer has heating coils, go to Step 3-14. If you see a heater box, label and disconnect the wires to the heating element's terminals. Set the volt-ohmmeter to the Rx 1 scale. If the element has two terminals, touch a probe to each terminal. The needle should move to about 10 ohms. If the element has three terminals, touch one of the probes to the middle terminal, the other probe to each of the other two terminals. The meter should read about 20 ohms each lime.
To see if the element has shorted to ground, set the volt-ohmmeter to the R x 10 scale. Touch one probe to the bare metal of the heating duct and the other probe to each of the element's terminals. The meter needle should not move, indicating no connection. If the element fails any test, replace it.
----- Step 3-12. Removing the heater box. Remove the screws that hold the
heater box to the bottom of the cabinet. The heater box might also be fastened
at the top. In this case, raise the top panel of the dryer and remove the screw
that holds the heater box to the back of the cabinet. Disconnect the wires
to the thermostat and lift the heater box slightly.
Then remove it down and out from the back of the cabinet.
Step 3-13. Replacing the heating element. Remove the screw at the bottom of
the heater box and carefully slide out the element. Look for cracked insulators
or COILS broken and sagging coils. Install the new element and remount the
heater box in the reverse order.
----
Step 3-14. Testing the heating coils. If the dryer has heating coils mounted
in a housing behind the drum, unplug the dryer and raise the top panel. Locate
the coils' three terminals in the left rear of the cabinet. Label the wires
and draw a wire diagram. Disconnect the wires from the terminals. Set the volt-
ohmmeter to the R x1 scale. Touch one probe to the left (common) terminal and
the other probe to each of the other two terminals. In each test, the needle
should move to about 5 or 10 ohms, showing continuity. To test if the element
is shorted to ground, touch one probe to the heater housing and the other probe
to each of the terminals. The needle should not move for any of these tests.
If your results are different, replace both coils with new ones.
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Step 3-15. Preparing to remove the drum. To replace the coils, you have to
take out the drum. With the dryer unplugged, raise the top panel of the dryer.
Remove the toe panel and the front panel from the dryer.
Step 3-16. Removing the drive belt. Underneath the drum, push the idler pulley
toward the motor and remove the belt from the motor pulley. Carefully lift
the drum and slide it out from the front of the cabinet.
----- Step 3-17. Removing the retaining clip.
If the drum won't move, the shaft might be held by a retaining clip at the rear of the drum. Remove the small access panel from the rear of the cabinet. Loosen the grounding strap and move it out of the way. Use needle-nose pliers to pry the retaining clip from the shaft.
Step 3-18. Removing the drum. You should now be able to remove the drum through
the front of the cabinet. With the drum removed, you should have access to
the heating coils located in the heater housing behind the drum.
--------
Step 3-19. Removing the coils.
Look for breaks in the coils or insulators. Draw a wiring diagram before removing the old coils. To remove the coils, use wire cutters to cut the coils near the terminals. Gently remove the coils through the insulators. The terminals are just threaded studs held in place by nuts and washers. Use a small wrench to remove the nuts holding the terminals to the heater housing. Keep the ceramic insulators, but if the terminals are burned or corroded, install new ones.
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Step 3-20. Installing new coils.
Hook the end of the new coil around the terminal. Install another washer and nut so that the end of the coil is pressed tightly between two washers. Now place the ceramic insulator back on the terminal and mount the terminal in the hole on the heater housing. Install a terminal for the inside coil in the middle hole and the terminal for the outside coil in the right hand hole. Carefully thread the two coils clockwise through the proper insulators. Now connect the two free ends around the remaining terminal and install the terminal and insulators in the remaining hole. Reassemble the dryer in the reverse order.
----
Step 3-21. Replacing drum drive belt.
Unplug the dryer. Depending on the dryer, you have to either remove the rear panel or remove the toe panel and raise the top panel of the dryer. Now remove the front panel.
------ Step 3-22. Removing the belt. Beneath the drum you should see the
drive belt looped around the idler pulley and the motor pulley. Note how it
is looped around the pulleys. Push the idler pulley toward the motor and disconnect
the drive belt from the idler and motor pulleys.
Step 3-23. Installing a new belt. Lift the drum slightly and slide the old
belt out the front of the cabinet. Install the new belt with the groove side
down against the drum. Depending on the type of dryer, reconnect the drive
belt under the idler pulley and over the motor pulley, or over the idler pulley
and under the motor pulley, according to how the old one was looped. Now rotate
the drum by hand to make sure the belt is properly installed. Reassemble the
dryer.
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